Hero Future Energies has commissioned the country’s first large-scale hybrid renewable energy project — a combination of sun and wind power — in Karnataka’s Raichur district.

The company has added a 28.8 MW solar project to an existing 50 MW wind project set up two years ago.

A hybrid project has several advantages over a standalone solar or wind project, including saving on land, company insiders.

“Many of the solar panels have been installed in the spaces between the turbines,” Rahul Munjal, chairman at Hero Future Energies, said while inaugurating the project.

Solar projects need about five to seven acres of land per megawatt depending on the technology used, and though Hero did acquire some additional land for the solar project, it was far less than it would have had to for a standalone project of similar size, officials said.

Also, both wind and solar are ‘infirm’ sources of power in that their supply varies according to the speed of the wind or the intensity of solar radiation. By combining the two the project can supply steady power for a longer period in a day than standalone wind or solar plants, and improve its overall plant load factor (PLF). Wind speeds are usually highest early in the morning and at night, while sunshine is available only during the day.

“It helps to smoothen out the supply to the grid,” Munjal said. “It also optimises transmission cost. We have a single 24 km long line that goes from here to the substation. If we had two separate projects, we would need two separate lines, run by two separate teams. A hybrid project also helps in forecasting and scheduling, making forecasting more accurate,” he said.

The project is a group captive one, with a number of private companies buying power from it directly at mutually agreed tariffs.

Siemens Gamesa was contractor for both the solar and wind projects, and also provided wind turbines for the plant.

Though the combined plant has a total capacity of 78.8 MW, the transmission line so far is capable of evacuating only up to 50 MW.

If hybrid projects make more sense, why has it taken so long since India began its renewable energy programme for the first hybrid project to come up? It is because the government has no policy for such projects yet.

Draft guidelines for hybrid projects were circulated in mid-2016, but it was not finalised. There is no clarity yet on the tariff such projects can charge, and no state-owned discom will buy their power.

“I wish we could sell to discoms, but we can’t since they don’t have a price,” said Munjal. “Everyone is waiting for a government policy, for a tender or a document or a price, which has not happened. Hybrid plants cannot sell to the government yet. You can build one if it is a group captive project.”

Nor can those interested in hybrid projects participate in either solar or wind auctions, because the terms have not been set.

The main challenge for hybrid projects is finding locations that have both strong winds and good solar radiation. “If you want to optimise on both, there are very few places,” said Munjal. “Wind power is available in only eight states in the country. Solar is everywhere. It is possible to get a great wind site with decent solar, but it will be rare to get a great wind site with great solar as well.”

Hero Future Energies currently has around 1,200 MW of installed wind and solar projects, with another 500 MW being built and 300 MW more in the pipeline.